The chemical structure of a fuel-rich, non-sooting (C:O=0.773) premixed propene-oxygen-argon flame at 50 mbar was studied and compared with experimental results. The chemical kinetic pathways leading to polycyclic aromatic hydrocarbons (PAHs) are identified. The reaction pathway for aromatic growth includes successive growth by small hydrocarbons, combinative reaction sequences and the cyclopentadienyl pathway. Additionally, the influence of experimental errors of the temperature profile, used as an input for the calculations, on the computed species concentrations is demonstrated. The model shows satisfactory agreement with the measured results. Benzene was predicted to be formed primarily by the recombination of propargyl. It was found that the growth of aromatic compounds is caused mainly by the reaction of side-chains of the PAH with propargyl, the cyclopentadienyl pathway and combinative steps, whereas the H abstraction C2H2 addition channel cannot account for the early reaction steps of PAH growth in the flame investigated here.